Fall flush concerns for trout
On an October day in Glenwood Canyon last year, Sherman Hebein looked into the Colorado River and was appalled.
“I saw this big batch of sediment coming down the river and I said, “What’s going on?'”
It was more than just a question of idle curiosity. Hebein, based in Montrose, is senior aquatic biologist on the Western Slope for the Colorado Division of Wildlife.
He, other Division of Wildlife officials and Western Slope anglers all are concerned about Xcel Energy’s decision to flush sand out of the reservoir behind the Shoshone Dam in Glenwood Canyon last fall.
The result was a heavy load of sediment dumped downstream during the brown trout spawning season.
“It was just a mudflow,” said Jeff Dysart, co-owner of Alpine Angling in Carbondale and Roaring Fork Anglers in Glenwood Springs.
The Division of Wildlife has taken its concerns to Xcel, which uses the reservoir to divert water through tunnels to its Shoshone hydroelectric plant three miles downstream in the canyon. The power company has responded with a promise to try to do future flushes in the spring rather than the fall, when runoff from snowmelt boosts flows and reduces the environmental impacts.
“We will make every attempt possible to try to limit and not do any releases and flush water out of the dam in the fall,” said Dan Brown, the plant production supervisor for Xcel’s Colorado hydro operations.
Pat Tucker, area manager in Glenwood for the Division of Wildlife, said some anglers would prefer to hear more ironclad assurances from Xcel.
For now, he said, “The proof will be when they have to do this again, how do they handle it.”
Meanwhile, the U.S. Army Corps of Engineers has begun looking into whether it has any authority under the Clean Water Act to require Xcel to obtain a federal permit before future flush operations.
Some maintenance activities on a reservoir are exempted from permitting, said Mark Gilfillan, biologist and regulatory project manager for the Army Corps of Engineers’ Colorado/Gunnison Basin regulatory office in Grand Junction. The Corps of Engineers was notified of the flushing Oct. 27, immediately after it began.
“Some of the activity that we observed may be exempt from the Clean Water Act and some of it may not,” said Gilfillan. “We do have, obviously, concerns; we’re still collecting information.”
Hebein said the concerns behind such a sediment flush in the fall are many-fold.
The abrupt change in water flow is one. Brown trout spawn on the edges of the river. If the trout spawn while the reservoir is being flushed, and then the water reverts to normal level, many of the brown trout eggs can be left high and dry.
A fall sediment flush also contaminates the river far more than in the spring, because the lower water volume increases the concentration of the sediment in the river.
Hebein said spores of a fungus that attacks brown trout also back up in reservoirs, but are released during a flush, threatening fish downstream. Trout already are weakened during spawning. The sediment-filled water makes them further stressed and vulnerable to the fungus.
Sediment also smothers some aquatic insects, killing off food that can be important to trout during their various life stages, Hebein said.
“All told, there can be a serious consequence to a small flush,” he said.
Dysart agreed. “It’s not good to have three or four inches of mud sitting on the bottom of the river all winter,” he said.
Hebein said he didn’t hear of many dead fish floating on the surface due to the flush, and doesn’t think its impacts were that direct or easy to quantify. It could take another year of population counts to get a better sense of the damage done.
Also, an average or above-average runoff this spring would help to clean out the river and reduce the impacts of the sediment, Hebein said.
Besides threatening trout, last year’s flush made the water too muddy to fish, Dysart said. He said the timing of the flush didn’t hurt his guide business much because it came at the end of the season. But he added, “A lot of the locals that like to get out and fish, they couldn’t do it.”
During the spring runoff, the Colorado is muddy and unfishable anyway. And the high water would carry the sediment from flushing the reservoir much farther downstream, all the way to Lake Powell, Dysart said.
“It just makes sense,” he said of flushing the reservoir in the spring.
Turnover a factor
The flushing isn’t required every year. Xcel releases water about every four years to eliminate a sandbar that forms near the intake tubes leading to its power plant. But the fact that the reservoir isn’t flushed more frequently may be part of the problem.
Tucker began his Glenwood job in September 1999. Brown started on his job at Xcel in June. So neither of them knows anything about past fall releases, or any possible agreements to try to avoid them.
Meanwhile, the Colorado River “has become more of a player” among anglers in recent years, for a variety of factors, Dysart and Tucker agreed. That has made the consequences of endangering the fishery more severe.
In a letter to Tucker, Brown commits Xcel to making “reasonable efforts” to flush the reservoir in the spring rather than fall.
He said the company also will make the same commitment in the case of routine maintenance, upgrades, inspections and similar work. Brown said Xcel will notify departments and individuals responsible for scheduling this work so they are aware of the timing sensitivities involved.
Lastly, Brown said that in emergency situations, Xcel will work to resolve the problem quickly. It also will notify the state Division of Water Resources of any operational changes at Shoshone, so that agency can notify the Division of Wildlife and other state agencies as necessary.
SIDEBAR: Xcel: Deeper water issues at stake
by Dennis Webb
Glenwood Springs Correspondent
Releasing water in the fall during brown trout spawning would have fewer environmental impacts than letting Xcel’s Shoshone Power Plant go out of service, a company official says.
That’s why Xcel won’t make a 100 percent guarantee against releasing water from the Shoshone Dam in the fall, said company spokesman Steve Roalstad.
Roalstad said the company will do everything in its power to do releases in the spring. But he said that if emergency maintenance requiring water releases is needed in the fall, river systems across much of western Colorado would be impacted if Xcel shut down the plant rather than doing the work.
If the plant is shut down, Xcel would have to stop its call on the river. That means Denver Water could store the water upstream, lowering water levels and impacting fisheries all along the Colorado, he said.
“That’s how important it is for us to keep our plant operating,” Roalstad said. “It’s important for us to maintain the water flows on the river.”
The Shoshone water plant is a minor producer of power for Xcel. But it has one of the most senior water rights on the Colorado River. That means Xcel is legally entitled to ensure that it has adequate water flow even when Denver Water, which has a more junior right, wants to divert and store it.
Roalstad said Xcel also needs water for its Cameo coal power station east of Grand Junction. If water on the Colorado River is reduced, Xcel would need to call on its other water rights on the Arkansas, Fryingpan and Roaring Fork rivers, impacting those waterways as well.
Streamflow reductions also can affect supplies available to municipal users, and the quality of those supplies, said Roalstad. For example, Rifle and Clifton treat Colorado River water for municipal use. If the river’s water volume goes down, the concentration of salt and other contaminants goes up, increasing the cost of treatment.
Roalstad said Xcel wants to accommodate the desire of anglers and not conduct fall releases from Shoshone. But if the company can’t do repair work in a fall emergency, “you’re looking at a devastating impact to drainages throughout the entire state. Hundreds of miles of fishing water would be changed dramatically,” he said.
Chips Barry, manager for Denver Water, said his agency is open to considering whether to withhold exercising its water rights if Xcel ever faced a choice between shutting down the plant or releasing water on spawning brown trout so it could perform repairs.
“We would be more than willing to be part of a discussion about how our operations might affect or not affect the river, the power plant and brown trout. What the decision would be is impossible to say,” Barry said.
He noted that even if Denver Water agreed to not exercise its water rights, a handful of other water users could exercise their own rights. So any agreement for dealing with an emergency involving the Shoshone plant would need to be more widespread.
He also takes issue with the notion that Denver Water affects fisheries by depleting downstream water.
“Nobody’s ever said that there’s a fish problem,” he said.
Rather, he sees a benefit to water being used within the state rather than running past Shoshone, even when the plant is out of operation. He thinks the heart of the controversy over water flushes from Shoshone is between anglers and Xcel.
“Denver Water has nothing to do with d Barry. “My sense is we’re probably not a real player in this at all.”